Vehicles, such as recreational vehicles, are often parked at campsites or other locations on uneven terrain. Consequently, the comfort of the occupants of the vehicle while eating, sleeping, etc. Within the vehicle, as well as the proper operation of some appliances such as refrigeration devices, may be adversely affected by the out-of-level orientation of the vehicle. Similarly, certain industrial devices require a level orientation for proper operation and are therefore mounted on platforms which may be leveled according to the teachings of the present invention. For simplicity, the remainder of this specification will describe the invention as used to level a vehicle although the apparatus and method described herein may have other applications.
It is known to employ jacks, blocks, or even hydraulically driven extendible legs mounted to a vehicle, to raise the low portions of the vehicle in an attempt to level a vehicle. Obviously, manual methods, such as using jacks and blocks, for leveling a vehicle the size of a recreational vehicle are undesirable. Manually leveling a vehicle may require raising one corner of the vehicle at a time, thereby inducing cross-frame stresses which may damage the vehicle frame. Additionally, manual jacks are potentially dangerous, time-consuming to use, inaccurate, and inconvenient, especially in bad weather or in cold or muddy conditions.
Manual actuation of hydraulically-driven extendible legs mounted to the vehicle frame is an improvement on the use of jacks to level a vehicle. However, even a skilled user attempting to level a vehicle by individually actuating extendible legs mounted to the vehicle may over extend a leg such that cross-frame stresses are imposed upon the vehicle. Additionally, the process of extending individual legs, manually checking the orientation of the vehicle using a level sensor, then further adjusting the orientation of the vehicle by extending another leg, is time consuming and inaccurate.
Accordingly, an illustrative embodiment of the present disclosure provides an apparatus for automatically leveling a vehicle. The apparatus comprises a right front leg, a left front leg, a right rear leg, and a left rear leg mounted to the vehicle. Each leg is independently adjustable between a stowed position and an extended position wherein the leg engages the ground. A sensor is mounted to the vehicle to sense the pitch and roll of the vehicle relative to a reference level plane. The sensor produces an orientation signal representing the vehicle pitch and roll. A controller is coupled to the legs and the sensor. The controller responds to an operator command to level the vehicle relative to the reference level plane by actuating the legs such that they move from their stowed position to their extended position. The orientation signal determines an end and a side of the vehicle which is above the reference level plane and then alternates between adjusting the end and the side downwardly by retracting the legs at the end, and retracting the legs at the side. Each leg is retracted for a first predetermined period of time during each downward adjustment.
In the above and other illustrative embodiments, the apparatus may also provide: the sensor providing the orientation signal to the controller indicating a change in the vehicle orientation after each leg engages the ground and extends sufficiently to affect the vehicle orientation; the controller interpreting the orientation signal after each adjustment to determine whether either the end or the side has passed through the reference level plane; upon determining that one end or side has passed through the reference level plane, the controller alternates between adjusting the one end or side upwardly by extending the legs at the one end or side for a second predetermined period of time which is less than the first predetermined period of time, and continuing to adjust the other end or side downwardly by sequentially retracting the legs at the other end or side for the first predetermined period of time; the controller changes the direction of adjustment of the end and the side each time the end and the side pass through the reference level plane as indicated by the orientation signal and reduces the period of time for extending or retracting the legs at the end and the side with each passing of the reference level plane; switches for individually actuating the legs; and four leg sensors mounted adjacent each of the respective legs, each leg sensor being connected to the controller to provide a signal indicating that the respective leg is in its stowed position.
Another illustrative embodiment of the present disclosure provides an apparatus for automatically leveling a vehicle. The apparatus comprises a plurality of legs, a sensor and a controller. Each of the legs is movable to a retracted stowed position to allow the vehicle to travel. Each of the legs is also movable to an extended use position to engage a ground surface prior to leveling the vehicle. The sensor is mounted to the vehicle to sense pitch and roll of the vehicle relative to a reference level plane. The sensor produces an orientation signal representing the vehicle pitch and roll. The controller is coupled to each of the legs and to the sensor, and monitors the orientation signal received from the sensor and in response to that signal the controller causes at least one of the legs to retract to move the vehicle downwardly relative to the ground surface, for orienting the vehicle with the reference level plane within a tolerance.
In the above and other illustrative embodiments, the apparatus may also provide: the sensor providing the orientation signal to the controller indicating a change in the vehicle orientation after each leg engages the ground and extends sufficiently to affect the vehicle orientation; the controller interpreting the orientation signal after each adjustment to determine whether a portion of the vehicle has passed through the reference level plane; wherein upon determining that a portion of the vehicle has passed through the reference level plane, the controller alternates between adjusting an end upwardly by extending legs for a second predetermined period of time which is less than the first predetermined period of time, and continuing to adjust another end downwardly by retracting the leg at this other end for the first predetermined period of time; upon determining that a portion of the vehicle has passed through the reference level plane, the controller alternates between adjusting an end upwardly by extending the legs at the end for a predetermined period of time, and continuing to adjust another end downwardly by retracting the legs at this other end for another predetermined period of time; switches for individually actuating the legs; and leg sensors mounted adjacent each of the respective legs, wherein each leg sensor being connected to the controller to provide a signal indicating that the respective leg is in its stowed position.
Another illustrative embodiment of the present disclosure provides an method for automatically leveling a vehicle. The vehicle comprises a plurality of legs which are each attached to the vehicle such that each of the legs is movable between retracted and extended positions, a sensor mounted to the vehicle to sense pitch and roll of the vehicle and which provides an orientation signal representing the pitch and roll, and a controller coupled to the legs and the sensor. The illustrative method comprises: extending each leg until it engages a ground surface; comparing the orientation signal produced by the sensor to the reference level plane after all legs have engaged the ground; determining a high portion of the vehicle relative to the reference level plane; retracting at least one of the legs corresponding to that high portion for a determined actuation period; and determining whether the high portion of the vehicle has moved through the reference level plane after the retraction of the at least one of the legs.
In the above and other illustrative embodiments, the method may also provide the steps of: determining a low portion of the vehicle relative to the reference level plane; extending at least on of the legs corresponding to a low portion of the vehicle for a determined actuation period; determining whether the low portion of the vehicle has moved through the reference level plane after the extension of the at least one of the legs; and changing direction of movement of the vehicle every time it passes through the reference level plane as indicated by the orientation signal, and reduces the period of time for extending or retracting the legs of the vehicle with each passing of the reference level plane.
Additional features and advantages of the apparatus and method for automatically leveling an object will become apparent to those skilled in the art upon consideration of the following detailed description of the illustrated embodiment exemplifying the best mode of carrying out the apparatus and method for automatically leveling an object as presently perceived.
Corresponding reference characters indicate corresponding parts throughout the several views. The exemplification set out herein illustrates embodiments of the apparatus and method for automatically leveling an object, and such exemplification is not to be construed as limiting the scope of the apparatus and method for automatically leveling an object in any manner.